Integrated circuitry is typically fabricated on and within semiconductor substrates, for example relative to bulk semiconductor substrates and in semiconductor-on-insulator substrates. One exemplary technique for isolating different areas of circuitry includes the fabrication of trench isolation within the substrate, for example a bulk monocrystalline silicon substrate. For example, trenches are etched within a bulk semiconductor substrate and thereafter filled with an insulating silicon dioxide material.
The trenches might be lined with one or more insulative materials in addition to a primary or bulk insulative and/or semiconductive material(s). For example, isolation trenches might be lined with a thermal silicon dioxide layer grown from sidewalls of the trenches where such comprise silicon. A thin silicon nitride layer might be deposited thereover as a stress buffer and/or diffusion barrier layer. The thermally grown silicon dioxide might also be formed considerably later in the process, or might be eliminated. Regardless, it is typically desirable to leave some of the isolation material formed within the trenches to be projecting from the semiconductor substrate material at the conclusion of the processing. This typically results from an etch of silicon nitride which is typically received over the semiconductor substrate adjacent isolation material projecting from the respective trenches.
The invention was directed to overcoming problems and issues as described above, although such is in no way so limited. The invention is only limited by the accompanying claims as literally worded, without interpretative or limiting reference to the specification, and in accordance with the doctrine of equivalents.